1. Field of the Invention
This invention relates generally to a semiconductor fabrication process, and, more particularly, to identifying a potential cause of a fault in the semiconductor fabrication process based on an output from a process controller.
2. Description of the Related Art
There is a constant drive within the semiconductor industry to increase the quality, reliability and throughput of integrated circuit devices, e.g., microprocessors, memory devices, and the like. This drive is fueled by consumer demands for higher quality computers and electronic devices that operate more reliably. These demands have resulted in continual improvements in the manufacture of semiconductor devices, e.g., transistors, as well as in the manufacture of integrated circuit devices incorporating such transistors. Additionally, reducing the defects in the manufacture of the components of a typical transistor also lowers the overall cost per transistor as well as the cost of integrated circuit devices incorporating such transistors.
During the fabrication process, various events may take place that affect the performance of the devices being fabricated. That is, variations in the fabrication process steps may result in device performance variations. Factors, such as feature critical dimensions, doping levels, contact resistance, particle contamination, etc., all may potentially affect the end performance of the device. Various tools in the processing line are controlled, in accordance with performance models, to reduce processing variation. Commonly controlled tools include photolithography steppers, polishing tools, etching tools, and deposition tools. Pre-processing and/or post-processing metrology data is supplied to process controllers for the tools. Operating recipe parameters, such as processing time, are calculated by the process controllers based on the performance model and the metrology information to attempt to achieve post-processing results as close to a target value as possible. Reducing variation in this manner leads to increased throughput, reduced cost, higher device performance, etc., all of which equate to increased profitability.
Semiconductor manufacturing processes, which have become more reliable and robust over the past few years, may include a plurality of processing tools that cooperate with each other to process semiconductor devices, such as microprocessors, memory devices, ASICs, etc. To verify that the processing tools are operating within acceptable parameters, it has become increasingly desirable to monitor the operating conditions of such processing tools.
Today""s semiconductor manufacturing processes may include an intricate network of multiple processing tools for manufacturing semiconductor devices. Linking multiple processing tools may provide numerous advantages in the manufacture of semiconductor devices, but there can, however, be some drawbacks, particularly from the standpoint of troubleshooting problems or faults because of the system dynamics and the generally closed-loop nature of the manufacturing system. For example, identifying the real underlying cause of a fault may prove to be challenging because the effects of even a single fault can easily permeate through the manufacturing process, thereby increasing the number of variables that may need to be considered before the true source of the fault can be identified. Failing to timely identify the source of the detected faults may naturally delay any potential corrective measures that can be taken to address the problem. Because of these delays, the operation of the semiconductor manufacturing process may be adversely affected, thereby resulting in a potential increase in costs for the manufacturer and consumer.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.
In one embodiment of the present invention, a method is provided for identifying a cause of a fault based on a process controller output. The method comprises processing at least one workpiece under a direction of the controller, detecting a fault associated with the processing of the at least one workpiece and providing fault information associated with the detected fault to the controller. The method further comprises adjusting the processing of one or more workpieces to be processed next based on the fault information provided to the controller.
In another embodiment of the present invention an apparatus is provided for identifying a cause of a fault based on an output of a control unit. The apparatus comprises an interface and the control unit communicatively coupled to the interface. The interface is adapted to receive operational data associated with processing a lot of semiconductor wafers. The control unit is adapted to detect a fault based on the operational data, determine fault information related to a possible cause of the detected fault and provide the fault information to a process controller that is capable of enabling processing of a next lot of semiconductor wafers based on the fault information.
In a further embodiment of the present invention, an article comprising one or more machine-readable storage media containing instructions is provided for identifying a cause of a fault based on an output of a control unit. The one or more instructions, when executed, enable the processor to detect a fault based on receiving operational data associated with processing of one or more wafers, determine fault information related to a possible cause of the detected fault and provide the fault information to the control unit that is capable of adjusting a processing of at least one of a next wafer based on the fault information.
In a further embodiment of the present invention, a system is provided for identifying a cause of a fault based on an output of a control unit. The system comprises a processing tool, a fault detection and classification system and the control unit. The processing tool is adapted to provide operational data associated with a processing of one or more wafers. The fault detection and classification system is adapted to detect a fault based on the operational data, determine information related to a possible cause of the detected fault and provide the fault information. The control unit is adapted to adjust a processing of at least one wafer to be processed next based on the fault information.